[Radioisotope evaluation of the interaction between blood and vascular prostheses. Preliminary results]. / Evaluation radioisotopique de l'interaction sang-prothèses vasculaires. Résultats préliminaires.

In order to illustrate the phenomena which occur at the first contact between arterial prostheses and blood, an in vitro test is suggested which may be used to quantify the retention of the cruoric matrix using labelled compounds and confirming the nature by scan electron microscopy. Reorganisation of the cruoric matrix is dependent upon the scarring of polyesters which retain considerably more blood substances than microporous polytetrafluoroethylenes or the biological models dealt with, the course of which after implantation is closer to passivation.

[Absorbable synthetic clips and pulmonary excision]. / Clips synthétiques résorbables et exèréses pulmonaires.

From the beginning of this decade, two new, 2nd generation, resorbable synthetic materials--polydioxanone and lactomer--have been able to be molded into clips which, in contrast to metallic clips, are fitted with an original locking system preventing any slipping, either transversal or longitudinal, on the vessels. An experimental study was conducted to confirm their great reliability and perfect safety on large vessels (up to 8-9 mm) of large laboratory animals--both pulmonary and systemic vessels. Positive results justified their application to pulmonary vessels in humans during surgery, the pulmonary vessel being at a much lower pressure than in the main circulatory system. These new clips possess the advantages of metallic clips and resorbable synthetic threads without their inconveniences: rapidity, simplicity and ease of application, radio-transparency and complete inertia in magnetic fields enabling radiotherapy and modern postoperative investigations (scanner, NMR...) to be carried out.

[Absorbable synthetic clips and pulmonary excision. Our clinical experience]. / Clips synthétiques résorbables et exérèses pulmonaires. Notre expérience clinique.

Analysis of the first 50 clinical cases confirmed conclusions of experimental studies in large animals with respect to the use of absorbable synthetic clips formed of lactomer and polydioxanone. The advantages of clips when compared with ligatures include rapidity and simplicity of use and ease of insertion, even in regions difficult to approach surgically with the fingers. The advantages of clips of the absorbable synthetic type over conventional metallic material are: safety and reliability due to their locking system and the conservation of sufficient residual resistance, improved behavior in biologic media, radio-transparency and total inertia in magnetic fields compatible with postoperative radiation and modern medical imaging procedures (CT scan, IRM), and finally progressive resorption predictable by simple hydrolysis and then total disappearance after 6 to 7 months. With staplers of the TA and GIA type these clips make sutures and ligatures during lung resection surgery entirely automatic.

[Thermal isolation of the heart by means of a plastic foam pad during surgical cooling of the heart: experimental study]. / Isolation thermique du coeur par patin de mousse plastique au cours de la réfrigération chirurgicale du coeur. Etude expérimentale.

Maintenance of myocardial cooling during aortic clamping is a problem encountered currently during heart surgery. A plastic foam isolation pad was studied. Eight animals (pigs weighing 50 kg) were placed on extracorporeal circulation, 4 of them constituting the control group (A). Two coronary injections of a cardioplegic solutions were administered, the first at the time of aortic clamping and the second 30 minutes later. The myocardium of the 4 animals in the treated group (B) was isolated with the foam pad, and this significantly prolonged the "cold" effect of the cardioplegic. Ten minutes after injection of the cardioplegic, temperature of the total myocardial mass with isolation was between 10.7 and 12 degrees C, as against 16 to 18 degrees C in the reference group (p less than 0.05). By the 20th minute, the isolated myocardium was at approximately 15 degrees C as against 22 degrees C in group A (p less than 0.01). Finally, by the 30th minute, temperature in group B was 17 degrees C as against 23 degrees C in group A (p less than 0.01). Reheating of the heart was significantly slowed by thermal isolation, though the limit of 15 degrees C was reached by the 20th minute. To ensure that myocardial temperature remains below this limit when the foam pad is employed, further injections of cardioplegic solutions are necessary every 20 minutes.